| 王忠昶，杨庆.裂隙岩体贯通及锚固止裂路径有限元分析[J].,2010,(5):717-722 |
| 裂隙岩体贯通及锚固止裂路径有限元分析 |
| Finite element analysis for coalescence and consolidated response of joint rockmass |
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| DOI：10.7511/dllgxb201005017 |
| 中文关键词: 最短塑性区距离 I-II型复合裂纹 锚固止裂 扩展路径 |
| 英文关键词: mini-plastic zone distance I-II mixed mode crack reinforcement on crack prevention propagation path |
| 基金项目:国家自然科学基金资助项目(50979013)；辽宁省教育厅基金资助项目(2008z030). |
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| 中文摘要: |
| 压剪应力作用的裂隙岩体其裂纹尖端附近存在塑性屈服区．将裂隙岩体单元与锚索单元的节点完全重合，应用等效应变与降温法施加锚索单元的预应力，裂纹采用八节点等参单元退化后的奇异单元进行模拟，从应变角度出发，应用塑性区最短距离判据得到了不同锚固条件下含两条不同倾角共线裂纹的裂纹尖端附近的最短塑性区距离、裂纹的扩展方向、裂纹扩展后岩桥之间的有效距离等，并分析了裂隙岩体的锚固止裂机制．结果表明，预应力锚索加固对裂隙岩体的压缩效应远大于剪切效应．锚固条件下倾角为30°~60°的裂纹扩展后岩桥之间有效距离增大，锚固条件越好，裂纹尖端塑性区的最短距离越小，预应力锚索的加固止裂效果越明显．锚固附加应力场使得0°、90°裂纹附近岩体的正应力或侧向应力得到增加，锚固条件越好，裂纹尖端的塑性区最短距离越大，在进行锚固设计时，应合理布置锚固角． |
| 英文摘要: |
| The plastic zone near the crack tip of jointed rockmass is produced under the compression-shear stress condition. The nodes of jointed rockmass and anchor cables are overlapped one another. The pre-stress of anchor cable is loaded by equivalent strain and temperature method. The iso-parametric element with eight nodes is degenerated to singular element at crack tip to simulate crack. The mini-plastic zone distance near crack tip, extending orientation of crack, the effective distance between rock-bridges after failure of twain collinear cracks of different angles by mini-plastic zone distance judgment are obtained from strain point of view under different consolidated conditions. The mechanism on reinforcement of pre-stress anchor cable on crack prevention of different angles is analyzed. It is shown that the role of compression in crack rockmass is larger than the role of shear under consolidated condition. The effective distance between rock-bridges is increased under consolidated condition. The better consolidated condition is, the role of reinforcement on crack prevention to cracks of 30°~60° is more evident. The normal stress and lateral stress of jointed rockmass near crack are increased owing to additional stress of anchor cable, when the angles of crack are 0° and 90°. The better consolidated condition is, the larger the mini-plastic zone distance at crack tip is, and the reasonable consolidated angle is laid during the consolidated design. |
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